Electrical machine and methods of assembling the same

ABSTRACT

A fluid circulating assembly includes a fan impeller having an inlet ring and a rear plate that define a central chamber. The fluid circulating assembly includes an electrical machine having a rotor assembly, a stator assembly, and a housing. The electrical machine is coupled to the rear plate of the impeller such that the electrical machine is positioned entirely outside the central chamber. The housing includes a plurality of fins on a side of the housing opposite the rear plate. The fins extend axially away from the stator assembly. The assembly includes a duct attached to the housing. The duct covers a portion of the fins and extends radially outward from the housing towards an outer edge of the rear plate. The duct is configured to channel air over the portion of the fins to facilitate cooling the electrical machine.

BACKGROUND

The embodiments described herein relate generally to electricalmachines, and more particularly, to an axial flux electrical machineincluding an integrated controller for use in fluid circulating systems.

Many known commercial heating, ventilation, and air conditioning (HVAC)systems require air propulsion units. In addition to providing movementof air for HVAC systems, air propulsion units may be used in combinationwith condenser units and to supplement other heat transfer operations.Some known air propulsion units include motor driven fans. These fansinclude, for example, a centrifugal impeller type fan driven by a radialflux motor. However, some known radial flux motors and their mountingcomponents extend a certain distance into the fan cavity. This restrictsair flow through the fan and yields aerodynamic losses that adverselyaffect fan performance.

Moving the air propulsion unit outside of the fan cavity causes anoverall thickness of the assembly to increase significantly and furtherrequires that the fan be attached to a shaft of the motor using variouscoupling mechanisms attached to the fan. These known coupling mechanismsfurther add to the fan assembly thickness and introduce weight andcomplexity to the fan assembly. Furthermore, the cost is increased insuch fan assemblies due to the increased part count required forcoupling the fan to the motor shaft.

In addition, many known air propulsion units include an integratedcontroller attached to an end of the unit, thereby further increasingthe thickness of the fan assembly. To reduce the thickness of the airpropulsion unit, many known units include complex controller boardarrangements and layout that can add cost and complexity to the unit,and introduce localized heating from the heat generating components thatis not adequately dissipated.

BRIEF DESCRIPTION

In one aspect, a fluid circulating assembly having a rotation axis isprovided. The fluid circulating assembly includes a fan impeller havingan inlet ring and a rear plate that together define a central fanchamber. The assembly also includes an electrical machine including arotor assembly, a stator assembly, and a housing. The electrical machineis coupled to the rear plate such that the electrical machine ispositioned entirely outside the central fan chamber. The housingincludes a plurality of fins on a side of the housing opposite the rearplate. The plurality of fins extend axially away from the statorassembly. Furthermore, the assembly includes a duct coupled to thehousing. The duct covers a portion of the fins and extends radiallyoutward from the housing to the rear plate and towards an outer edge ofthe rear plate. The duct is configured to channel air over the portionof the fins to facilitate cooling the electrical machine.

In another aspect, a method for assembling a fluid circulating assemblyhaving a rotation axis is provided. The method includes providing a fanimpeller including an inlet ring and a rear plate that together define acentral fan chamber. The method also includes coupling an electricalmachine to the rear plate such that the electrical machine is positionedentirely outside the central fan chamber. The electrical machineincludes a rotor assembly, a stator assembly, and a housing. The housingincludes a plurality of fins on a side of the housing opposite the rearplate. The plurality of fins extend axially away from the statorassembly. The method further includes coupling a duct to the housing.The duct covers a portion of the fins and extends radially outward fromthe housing to the rear plate and towards an outer edge of the rearplate. The duct is configured to channel air over the portion of thefins to facilitate cooling the electrical machine.

In yet another aspect, a fluid circulating assembly is provided. Thefluid circulating assembly includes an electrical machine. Theelectrical machine includes a rotor assembly, a stator assembly, and ahousing. The housing includes an endshield. The endshield includes anannular center section configured to enclose the stator assembly, aplurality of fins extending axially away from the stator assembly, and aplurality of axially extending T-shaped T-slots spaced about a perimeterof the annular center section of the endshield.

In yet another aspect, a method of assembling a fluid circulatingassembly is provided. The method includes providing an electricalmachine including a housing having a plurality of axially extendingT-slots spaced about a perimeter of the housing. The method alsoincludes slidingly coupling a T-nut to each one of the plurality ofaxially extending T-slots. Furthermore, the method includes releasablycoupling each respective T-nut to a support bracket using at least onefastener. This enables the electrical machine to be slidingly coupled tothe support bracket via the T-nuts at an infinite number of locationsalong a length of the plurality of axially extending T-slots.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic perspective of an exemplary fluid circulatingassembly;

FIG. 2 is a cross-sectional view of the fluid circulating assembly takenalong line 2-2 of FIG. 1;

FIG. 3 is an enlarged view of a portion of FIG. 2 identified by box 3,showing an electrical machine of the fluid circulating assembly withouta fan impeller;

FIG. 4 is an exploded view of the electrical machine shown in FIG. 3;

FIG. 5 is an end view of a housing looking axially along a center axistoward an endshield;

FIG. 6 is an exploded view of the housing of FIG. 5 looking toward acover plate from the endshield;

FIG. 7 is an exploded view of the housing of FIG. 5 looking toward theendshield from the cover plate;

FIG. 8 is an enlarged view of a portion of FIG. 3 identified by box 8;

FIG. 9 is an exploded view of a hub drive for use with the electricalmachine shown in FIG. 3;

FIG. 10 is a front view of the hub drive shown in FIG. 9;

FIG. 11 is a side view of the hub drive shown in FIG. 9;

FIG. 12 is an exploded view of a mounting system for the electricalmachine shown in FIG. 3;

FIG. 13 is a side view of the fluid circulating assembly shown in FIG. 1coupled to a support bracket and positioned at an outward extent awayfrom an inlet nozzle support plate;

FIG. 14 is a side view of the fluid circulating assembly shown in FIG. 1coupled to the support bracket and positioned at an inward extent towardthe inlet nozzle support plate;

FIG. 15 is a schematic perspective of the fluid circulating assemblyshown in FIG. 1 mounted to the support bracket and including coolingducts;

FIG. 16 is an exploded perspective view of the endshield shown in FIG. 5having a controller assembly attached thererto;

FIG. 17 is an exploded perspective view of the endshield shown in FIG. 5having an alternative embodiment of the controller assembly attachedthererto;

FIG. 18 is a cross-sectional view of an alternative fluid circulatingassembly; and

FIG. 19 is a schematic perspective of the alternative fluid circulatingassembly shown in FIG. 18, showing a shaft/hub assembly for coupling afan impeller to the electrical machine shown in FIG. 3.

Although specific features of various embodiments may be shown in somedrawings and not in others, this is for convenience only. Any feature ofany drawing may be referenced and/or claimed in combination with anyfeature of any other drawing.

DETAILED DESCRIPTION

FIG. 1 is a schematic perspective of an exemplary fluid circulatingassembly 10. FIG. 2 is a cross-sectional view of fluid circulatingassembly 10 taken along line 2-2 of FIG. 1. In the exemplary embodiment,fluid circulating assembly 10 generates a flow of air in a forced airsystem, for example, without limitation, a residential or commercialheating, ventilation, and air conditioning (HVAC) system. Alternatively,fluid circulating assembly 10 generates a fluid flow in any type offluid circulating system that enables fluid circulating assembly 10 tofunction as described herein. In the exemplary embodiment, fluidcirculating assembly 10 includes a fan impeller 12 coupled to anelectrical machine 14. In the exemplary embodiment, electrical machine14 is an electric motor, and more specifically, an axial flux electricmotor, although, electrical machine 14 may function as either anelectric motor or an electric generator. Furthermore, fan impeller 12 isa centrifugal fan impeller, although, impeller 12 can be a pumpimpeller.

In the exemplary embodiment, fan impeller 12 includes a plurality of fanblades 16 (blades). Blades 16 are attached between a rear plate 18 andan inlet ring 20 (or front plate). Inlet ring 20 includes a central airinlet 22. In the exemplary embodiment, fan impeller 12 is a backwardcurved plug fan. Alternatively, fan impeller 12 may have any suitableblade shape or configuration that enables fluid circulating assembly 10to operate as described herein, for example, without limitation, abackward curved blade, an airfoil blade, a backward inclined blade, aforward curved blade, and a radial blade.

In the exemplary embodiment, rear plate 18 and inlet ring 20 arecoaxial, or substantially coaxial, and rotate about a center axis 24.Blades 16 are attached to rear plate 18 and/or inlet ring 20 such thateach blade 16 extends between rear plate 18 and inlet ring 20. In theexemplary embodiment, each blade 16 is attached to rear plate 18 andinlet ring 20 by mechanical bonding, such as welding. Alternatively,each blade 16 is attached to rear plate 18 and/or inlet ring 20 viamechanical fasteners, for example, without limitation, rivets, or viafeatures formed in rear plate 18 and/or inlet ring 20 such as anopening, for example, without limitation, a groove or a slot configuredto restrict an amount of movement of blade 16 between rear plate 18 andinlet ring 20 while enabling each blade 16 to operate as describedherein.

In the exemplary embodiment, during operation, air enters fluidcirculating assembly 10 substantially axially along center axis 24through central air inlet 22 and is deflected radially outward towardblades 16. Blades 16 are configured to draw the air through inlet 22into a central chamber 28 of fan impeller 12, i.e., blades 16 pull inair along center axis 24 and eject the air radially outward throughoutlet channels 26, where each outlet channel 26 is located betweenadjacent blades 16. The air passes between blades 16 and is pushedoutward through outlet channels 26 due to centrifugal force generated bythe rotating blades 16. Blades 16 are suitably fabricated from anynumber of materials, including sheet metal, plastic, or a flexible orcompliant material. Alternatively, blades 16 are fabricated from acombination of materials such as attaching a flexible or compliantmaterial to a rigid material, or any suitable material or materialcombination that enables blades 16 to operate as described herein.

FIG. 3 is an enlarged view of a portion of FIG. 2 identified by box 3,showing electrical machine 14 without fan impeller 12. FIG. 4 is anexploded view of electrical machine 14. In the exemplary embodiment,electrical machine 14 is an axial flux electric motor configured torotate fan impeller 12 about center axis 24. Electrical machine 14includes a stator assembly 30, a rotor assembly 32, and a pair ofbearing assemblies 34 a, 34 b coupled radially therebetween. Statorassembly 30, rotor assembly 32, and bearing assemblies 34 a, 34 b arepositioned concentrically, each including a central opening 35 orientedabout center axis 24.

Stator assembly 30 includes a stator core 36 that includes a pluralityof circumferentially-spaced stator teeth 38 that extend axially,substantially parallel to center axis 24. In the exemplary embodiment,stator core 36 is a laminated core. As defined herein, the laminatedcore is radially laminated, e.g., fabricated with a ribbon of materialwound into a core, or a series of concentric rings stacked one insidethe other to create a core of material, for example, soft iron orsilicon steel. Alternatively, stator core 36 may be a solid core stator.A solid core can be a complete, one-piece component, or can includemultiple non-laminated sections coupled together to form a completesolid core. Stator core 36 is fabricated from a magnetic material, suchas, for example, a Soft Magnetic Alloy (SMA) or a Soft MagneticComposite (SMC) material. Alternatively, stator core 36 is fabricatedfrom any ferromagnetic material that enables electrical machine 14 tofunction as described herein, such as, for example, steel or a steelalloy. The use of SMA or SMC materials in a solid core enable3-dimensional flux paths and facilitate reducing high frequency losses(e.g., losses at frequencies above 60 Hz) when compared with laminatedstator cores. The use of SMC or SMA materials also facilitatesincreasing control of an air gap 39, which facilitates improvingperformance and minimizing noise.

Between each pair of adjacent stator teeth 38 is a slot 40. Each statortooth 38 is configured to receive one of a plurality of insulatingbobbins 42 that includes a copper winding 44 would around an outersurface of each respective bobbin 42. Alternatively, each stator tooth38 includes copper winding 44 without bobbin 42. Electrical machine 14can include one copper winding 44 per stator tooth 38 or one copperwinding 44 positioned on every other stator tooth 38. Copper windings 44are electrically coupled to a controller assembly 46 for receivingelectrical current thereby inducing an electromagnetic field about apole of stator core 36. Controller assembly 46 is configured to apply avoltage to one or more of copper windings 44 at a time for commutatingcopper windings 44 in a preselected sequence to rotate rotor assembly 32about center axis 24. In the exemplary embodiment, electrical current isa three-phase alternating current (AC). Alternatively, the current isany type of electrical current that enables electrical machine 14 tofunction as described herein. In the exemplary embodiment, controllerassembly 46 functions to both accelerate and decelerate rotor assembly32.

In the exemplary embodiment, rotor assembly 32 includes a rotor diskassembly 48 having an axially inner surface 50 and a radially inner wall52 that at least partially defines opening 35. Rotor assembly 32 alsoincludes a plurality of permanent magnets 54 coupled to inner surface 50of rotor disk assembly 48. In one suitable embodiment, magnets 54 arecoupled to rotor disk assembly 48 using an adhesive. Alternatively,magnets 54 are coupled to rotor disk assembly 48 by a magnet retainingring or any other retention method that enables electrical machine 14 tofunction as described herein. In the exemplary embodiment, permanentmagnets 54 are symmetrical, which facilitates manufacturing by enablinga single magnet design for use with each magnet 54. Furthermore, eachmagnet 54 has a substantially flat profile which facilitates reducingwaste during manufacturing, and therefore, facilitates reducingmanufacturing cost. In the exemplary embodiment, permanent magnets 54are neodymium magnets. Alternatively, any suitable permanent magnetmaterial may be included that enables electrical machine 14 to functionas described herein, for example, without limitation, Samarium Cobaltand Ferrite. Rotor assembly 32 is rotatable within electrical machine14, and more specifically, rotatable within bearing assemblies 34 a, 34b about center axis 24.

In the exemplary embodiment, rotor disk assembly 48 is fabricated from asolid metal material, for example, without limitation, steel or iron.Alternatively, rotor disk assembly 48 is fabricated from, for example,an SMA material, an SMC material, or a powdered ferrite material, usinga sintering process. Similarly, as described above, stator core 36 isfabricated from a material that enables magnetic attraction betweenpermanent magnets 54 and stator core 36 to facilitate retaining rotordisk assembly 48 and bearing assemblies 34 a, 34 b in place withinelectrical machine 14 such that electrical machine 14 does not require ashaft. Rotor disk assembly 48 includes a shaft portion 49 that includesa step 51 configured to facilitate holding bearing assembly 34 a inplace. Shaft portion 49 includes a diameter (not shown) configured tocorresponding a diameter of bearing assemblies 34 a, 34 b. Furthermore,rotor disk assembly 48 includes a ring-shaped axially extending flange53 that extends outward from rotor disk assembly 48 toward fan impeller12 (not shown in FIG. 4).

In the exemplary embodiment, electrical machine 14 includes housing 56configured to provide a protective covering for electrical machine 14and controller assembly 46. In the exemplary embodiment, housing 56includes an endshield 58 having an integrated flange 60 that extendsaxially towards rear plate 18 of fan impeller 12 (shown in FIGS. 1 and2) from a perimeter of endshield 58. Furthermore, housing 56 includes acover plate 62 that is configured to couple to flange 60, therebyenclosing components of electrical machine 14 within housing 56. Housing56 is configured to maintain a stationary position of stator assembly30, bearing assemblies 34 a, 34 b, and controller assembly 46 duringrotation of fan impeller 12 and rotor assembly 32.

Housing 56 is shown in more detail in FIGS. 5-7. Endshield 58 isconfigured with two distinct sides; a component engaging side 100 asbest shown in FIG. 7 and a component cooling side 102 as best shown inFIGS. 5 and 6. Specifically, FIG. 5 is an end view of housing 56 lookingaxially along center axis 24 toward endshield 58, FIG. 6 is an explodedview of housing 56 looking toward cover plate 62 from endshield 58, andFIG. 7 is an exploded view of housing 56 looking toward endshield 58from cover plate 62.

In the exemplary embodiment, endshield 58 is cloverleaf-shaped, havingfour extension portions 64 extending radially outward from an annularcenter section 66. Alternatively, endshield 58 has fewer or more thanfour extension portion 64 and can have any shape that enables endshield58 to function as described herein. Each extension portion 64 isconfigured to retain a component of controller assembly 46 therein.Center section 66 includes a bearing locator 68 extending from an innersurface 70 of endshield 58 that facilitates retaining bearing assemblies34 a, 34 b (shown in FIG. 4) in place. Bearing locator 68 includesopening 35 that is formed as a stepped bore having a first step 72 and asecond step 74 defining increasingly smaller bore diameters. Bearingassembly 34 a is seated in opening 35 in the smaller diameter portiondefined by second step 74. A bearing retainer plate 76 is secured toendshield 58 to secure bearing 34 a in place. Retainer plate 76 isattached to endshield 58 using a plurality of mechanical fasteners 80.Bearing assembly 34 b is seated in opening 35 in the largest diameterportion defined by first step 72. Bearing locator 68 engages and locateseach bearing assembly 34 a, 34 b by engaging an outer race portion (notshown) to position and secure bearing assemblies 34 a, 34 b such thatbearing assemblies 34 a, 34 b are positioned radially inward from andconcentric with stator assembly 30 (shown in FIG. 4).

In the exemplary embodiment, endshield 58 includes a plurality ofcooling fins 78 (best shown in FIG. 6) extending from component coolingside 102. Fins 78 facilitate cooling electrical machine 14 and extendgenerally radially outward from annular center section 66. Furthermore,fins 78 extend axially outward from endshield 58. In the exemplaryembodiment, fins 78 are formed in substantially parallel groups thatextend generally radially outward along each extension portions 64,where each group of fins 78 is formed substantially transverse to eachrespective adjacent group of fins 78. Alternatively, fins 78 canarrangement in any arrangement that enables electrical machine 14 tofunction as described herein.

In the exemplary embodiment, a flange 82 extends axially inward fromsurface 70 a distance substantially equal to a length of each statortooth 38. Flange 82 facilitates substantially isolating stator assembly30 from controller assembly 46 within endshield 58. This facilitatesreducing electrical interference or short circuiting between theassemblies. In one embodiment, endshield 58 is fabricated from castaluminum. Alternatively, endshield 58 is fabricated from any materialthat enables endshield 58 to function as described herein, for example,without limitation, an aluminum-tin-nickel alloy, or steel. Further, inthe exemplary embodiment, endshield 58 is a single piece cast component.Alternatively, endshield 58 is fabricated as several separate componentsthat can be coupled together to form endshield 58.

In the exemplary embodiment, each of extension portions 64 includespockets 104 of various shapes and sizes. Pockets 104 are formed in innersurface 70 and extend axially outward toward fins 78. Each one ofpockets 104 is configured to conform to a specific shape of a componentof controller assembly 46 to enable controller assembly 46 to beenclosed within housing 56. Furthermore, each of extension portions 64include a plurality of mounting bosses 106 configured to accept amechanical fastener to hold a circuit board (not shown in FIGS. 5-7) ofcontroller assembly 46.

In the exemplary embodiment, at least one of extension portions 64includes one or more power inlet openings 108. Inlet openings 108 arecircular in shape and extend through flange 60 of endshield 58. In theexemplary embodiment, one of extension portions 64 includes three inletopenings 108 extending through the outer most extent of extensionportion 64. Inlet openings 108 are configured to accept an end user'selectrical power supply lines for attaching to controller assembly 46.In alternative embodiments, inlet openings 108 and be any shape and anynumber that enables endshield 58 to function as described herein. In theexemplary embodiment, the extension portion 64 that includes inletopenings 108 is also configured with a terminal cover 110. Terminalcover 110 is fabricated to be a removable portion of endshield 58 tofacilitate access to controller assembly 46 for attaching an end user'selectrical power supply lines to controller assembly 46 without the needto completely disassemble electrical machine 14. In the exemplaryembodiment, terminal cover 110 extends about a perimeter of therespective extension portion 64 and is offset radially outward adistance from center section 66 of endshield 58. Extension portion 64includes a lip 112 having a plurality of mounting holes 114 forreceiving mechanical fasteners 116. Terminal cover 110 includes aplurality of holes 118 that correspond to mounting holes 114 forreceiving mechanical fasteners 116. In alternative embodiments, terminalcover 110 can have any size and shape that enables endshield 58 tofunction as described herein.

In the exemplary embodiment, housing 56 also includes cover plate 62,which is shaped to conform to the perimeter shape of endshield 58. Inthe exemplary embodiment, cover plate 62 is coupled to endshield 58using a plurality of mechanical fasteners 84. Cover plate 62 includes anannular inner flange 86 that defines an opening 88 in cover plate 62.Inner flange 86 extends axially away from both an outer surface 90 andan inner surface 92 of cover plate 62. Inner flange 86 is configuredfacilitate reducing flexing of cover plate 62 and to provide and innermost structure for a sealing channel 94. Sealing channel 94 is formed oninner surface 92 and is defined by inner flange 86 and an outer flange96 that has a larger diameter and is radially offset from inner flange86. Channel 94 is shaped and configured to correspond to flange 53 ofrotor disk assembly 48.

FIG. 8 is an enlarged view of a portion of FIG. 3 identified by box 8.In the exemplary embodiment, sealing channel 94 and flange 53 cooperateto form a tortuous sealing path between rotor disk assembly 48 andhousing 56. In the exemplary embodiment, channel 94 includes a pluralityof fiber filaments 121. Each filament 121 is a fine, hair-like structurefabricated from an electrically conductive material. For example,without limitation, filaments 121 can be fabricated from carbon fiber,stainless steel fiber, conductive acrylic fiber, or any other conductivefiber-type filament that enables filaments 121 to function as describedherein. In the exemplary embodiment, filaments 121 are adhered directlyor indirectly to a carrier structure (not shown) and positioned withinsealing channel 94. In operation, the filaments 121 are in electricallyconductive contact with rotor disk assembly flange 53 to facilitategrounding rotor disk assembly 48 to reduce electric charges thataccumulate on rotor disk assembly 48.

With reference to FIGS. 3 and 4, in the exemplary embodiment, statorassembly 30 is coupled to housing 56 via a plurality of fasteners 120extending through an axially outermost surface 122 of endshield 58.Furthermore, each one of bearings 34 a, 34 b is coupled to bearinglocator 68 of endshield 58 and bearing retainer plate 76 is secured toendshield 58 to secure bearing 34 a in place. Rotor assembly 32 ispositioned within housing 56 such that shaft portion 49 extends throughbearing assemblies 34 a, 34 b. In particular, rotor disk assembly 48seats against bearing assembly 34 b to facilitate holding bearingassembly 34 b in place against step 72, and step 51 of shaft portion 49seats against bearing assembly 34 a to facilitate holding bearingassembly 34 a in place against bearing retainer plate 76. A shaft seal124 is pressed into a center opening of bearing retainer plate 76 tofacilitate keeping debris from entering electrical machine 14, and inparticular bearing assemblies 34 a, 34 b. The location of bearings 34 a,34 b in endshield 58 is configured to control the width of air gap 39,which facilitates improving performance and minimizing noise. Coverplate 62 is coupled to endshield 58 to complete assembly of housing 56and to enclose electrical machine 14.

FIG. 9 is an exploded view of a hub drive 126 for use with electricalmachine 14. FIG. 10 is a front view of hub drive 126 and FIG. 11 is aside view of hub drive 126. In the exemplary embodiment, hub drive 126is ring-shaped and has an outer diameter D1 that is smaller than aninner diameter of flange 86 of cover plate 62. Hub drive 126 includes aplurality of fingers 128 extending radially inward from an inner surface130 of hub drive 126. Each finger 128 is generally triangular in shapeand includes a mounting hole 132 configured to correspond to arespective mounting hole in rotor disk assembly 48. In the exemplaryembodiment, hub drive 126 includes an axially extending lip 134 thatextends away from rotor disk assembly 48. Lip 134 has a diameter thatcorresponds to an opening in fan impeller 12, where lip 134 isconfigured to locate fan impeller 12 substantially concentric withelectrical machine 14 to facilitate reducing imbalances and vibrations.In the exemplary embodiment, hub drive 126 includes a substantially flatand smooth face 136 configured to mate directly to rear plate 18 of fanimpeller 12. Alternatively, face 136 has grooves, channels, or otherfeatures form therein and configured to facilitate moving air throughopening 35 in rotor shaft portion 49.

In the exemplary embodiment, hub drive 126 includes a plurality ofaxially extending mounting holes 138 formed in face 136. Holes 138 areconfigured to corresponding to respective mounting holes formed in rearplate 18 of fan impeller 12 and to receive fasteners. In the exemplaryembodiment, when mounted to rotor disk assembly 48, as best shown inFIG. 3, hub drive 126 has a thickness such that face 136 is positionedaxially outward from an extent of flange 86 of cover plate 62 to enablefan impeller (not shown in FIG. 3) to rotate about center axis 24without interfering with any portion of housing 56. In an alternativeembodiment, rotor disk assembly 48 is fabricated with the features ofhub drive 126, such that rotor disk assembly 48 can be coupled directlyto rear plate 18 of fan impeller 12 without the need to use hub drive126 therebetween.

FIG. 12 is an exploded view of a mounting system for electrical machine14. In the exemplary embodiment, a support bracket 150 is coupled toelectrical machine 14 via a plurality of T-nuts 152 and fasteners 154that mount to corresponding T-slots 156 formed in housing 56. Withreference back to FIGS. 5 and 6, endshield 58 of housing 56 includes aplurality of axially extending T-slots 156. In the exemplary embodiment,endshield 58 includes four T-slots 156, each located in a respectiveintersection between two adjacent extension portions 64. Each T-slot 156is identical in size and shape, having a T-shaped cross-section with thenarrow opening of each T-slot 156 facing radially outward from centersection 66 of endshield 58. As described above, each T-slot 156 extendsaxially such that each T-slot 156 is substantially parallel to centeraxis 24. Such a configuration enables electrical machine 14 to belocated in an infinite number of locations between the two extents ofT-slots 156. Each T-nut 152 is located within a respective T-slot 156and connected to a respective support arm of support bracket 150 by apair of fasteners 154. When fasteners 154 are loosely affixed to T-nuts152, electrical machine 14 can slide along the entire length of T-slots156. Fasteners 154 are turned to tighten with T-nuts 152 to affixelectrical machine 14 in any one of an infinite number of positionswithin the T-slots 156.

FIG. 13 is a side view of fluid circulating assembly 10 coupled tosupport bracket 150 and positioned at an outward extent away from aninlet nozzle support plate 158. FIG. 14 is a side view of fluidcirculating assembly 10 coupled to support bracket 150 and positioned atan inward extent toward inlet nozzle support plate 158. In the exemplaryembodiment, T-nuts 152 and fasteners 154 enable fluid circulatingassembly 10 to be accurately positioned with respect to inlet nozzlesupport plate 158, to enable a user to position fluid circulatingassembly 10 at an optimum location based on use conditions. Supportbracket 150 is coupled to inlet nozzle support plate 158 via itsmounting arms. As shown in FIG. 13, fluid circulating assembly 10 ispositioned at its outward extent of T-slots 156, such that supportbracket 150 does not contact fan impeller 12, yet a gap distance 160 isdefined between central air inlet 22 of impeller 12 and inlet nozzle 162of inlet nozzle support plate 158. Moreover, as shown in FIG. 14, fluidcirculating assembly 10 is positioned at its inward extent of T-slots156, such that central air inlet 22 of impeller 12 is positioned beyondinlet nozzle 162 of inlet nozzle support plate 158, and no gap distance160 is defined. The use of T-nuts 152 enables fluid circulating assembly10 to be positioned in any one of an infinite number of positionsbetween the inward and outward extents of T-slots 156.

FIG. 15 is a schematic perspective of fluid circulating assembly 10mounted to support bracket 150 and including cooling ducts 170. In theexemplary embodiment, electrical machine 14 includes a plurality ofcooling ducts 170 configured to be secured to endshield 58 of electricalmachine 14 using, for example, without limitation, mechanical fastenerscoupled to endshield 58. An advantage provided by ducts 170 is that theyare lightweight, easy to install, and can be used to convert air ejectedby fan impeller 12 to cool electrical machine 14. Each duct 170 issecurely coupled to one of extension portions 64 of housing 56 andextends over fins 78 of the respective extension portion 64. Each duct170 is substantially U-shaped in cross-section and forms a convergingtaper extending radially outward between center section 66 of endshield58 and an outer edge of rear plate 18. At the outer edge of rear plate18, duct 170 turns approximately 90 degrees and extends a predefineddistance 172 past the edge of rear plate 18. This enables duct 170 tocapture a portion of air ejected by fan impeller 12 and direct it overfins 78 to facilitate cooling electrical machine 14.

In an alternative embodiment, each duct 170 is substantially U-shaped incross-section and forms a converging taper that extends radially outwardbetween center section 66 of endshield 58 and an outer edge of rearplate 18, where duct 170 terminates, forming a radially extendingU-shaped channel over fins 78 and extension portions 64. In such anembodiment, an axial fan is coupled to rotor shaft portion 49 andpositioned proximate fins 78 of center section 66, such that air isforced over fins 78 and through ducts 170. In such an embodiment, axialfan is turned by electrical machine 14.

Ducts 170 are suitably fabricated from any number of materials,including a plastic sheet material or other sheet material. For example,in one suitable embodiment, ducts 170 are formed by a molding, forming,or extruding process used for fabricating parts from thermoplastic orthermosetting plastic materials and/or metals. Alternatively, ducts 170are fabricated from a combination of materials such as attaching two ormore sheet components together to form ducts 170. Ducts 170, however,are constructed of any suitable material, such as metal, that permitsducts 170 to function as described herein.

FIG. 16 is an exploded perspective view of endshield 58 havingcontroller assembly 46 attached thererto. As described above, controllerassembly 46 is coupled within housing 56 adjacent to stator assembly 30and rotor assembly 32, such that controller assembly 46 is positionedradially outward from stator assembly 30. Controller assembly 46includes more than one circuit board. In the exemplary embodiment,controller assembly 46 includes three circuit boards; a user interfaceboard 200, a rectifier board 202, and an inverter board 204.Alternatively, controller assembly 46 includes fewer or more circuitboards. For example, without limitation, in one alternative embodimentshown in FIG. 17, controller assembly 46 includes four circuit boards;one located in each extension portion 64, including user interface board200, rectifier board 202, inverter board 204, and an AC input board 206.In one suitable embodiment, controller assembly 46 includes two circuitboards such that power can be supplied directly to inverter board 204,thereby eliminating the need for rectifier board 202 and user interfaceboard 200. Moreover, in another suitable embodiment, a single circuitboard is used with controller assembly 46, such that all functions ofcontroller assembly 46 is integrated onto the single circuit board.

In the exemplary embodiment, user interface board 200, rectifier board202, and inverter board 204, i.e., controller assembly 46, are orientedsubstantially planar with respect to a back plane of stator assembly 30.As such, controller assembly 46 is not oriented axially with respect toelectrical machine 14. Alternatively, one or more of boards 200, 202,and 204, can be arranged perpendicular to an axial plane of statorassembly 30, thereby enabling alternative packaging layouts. Advantagesof breaking controller assembly 46 into modular board components,includes: enabling controller assembly 46 to be favorably arrangedaround the outside diameter of stator assembly 30; enabling controllerassembly 46 to share a common heat sink, i.e., endshield 58, with statorassembly 30; arranging the boards of controller assembly 46 to separateheat making devices onto separate boards; and separating controllerassembly 46 into major functions which can be built on separate boards.

In the exemplary embodiment, each one of boards 200, 202, and 204 issubstantially rectangular in shape and is sized to fit a respectiveextension portion 64 of endshield 58. This facilitates reducing the costof manufacturing different shape boards, for example, circular-shapedboards, that are used in axially-stacked motors. Alternatively, boards200, 202, and 204 can be fabricated in any number of shapes thatfacilitates operation of fluid circulating assembly 10 as describedherein. In the exemplary embodiment, boards 200, 202, and 204 aredistributed around stator assembly 30 and are separated into separatefunctions built on a respective one boards 200, 202, and 204. Usingseparate boards 200, 202, and 204 having distinct functions enables theindividual boards of controller assembly 46 to be updated withoutaffecting the entire controller assembly 46. Such updates can benecessitated by end users, new components, cost savings, or obsolescenceof current components. Furthermore, by separating controller assembly 46into discrete circuit boards, the circuit sections can be arranged indifferent configurations to alter the final shape of electrical machine14 and controller assembly 46. In addition, separating boards 200, 202,and 204 into separate functions facilitates spreading the heat makingcomponents of controller assembly 46 apart to facilitate cooling ofcontroller assembly 46.

In the exemplary embodiment, user interface board 200 is coupled to theextension portion 64 having inlet openings 108 and terminal cover 110.User interface board 200 includes a plurality of mounting holes 210formed therethrough, including one mounting hole 210 in each corner ofboard 200. A fastener 212 is passed through each hole 210 and coupled toendshield 58 to secure board 200 in place. The user then attaches hisinputs to user interface board 200, for example, without limitation, anAC input connection, a serial communication connection, and anyadditional discrete input/output digital or analog connections. Userinterface board 200 outputs the AC current and a serial communicationsignal and receives a low voltage direct current (DC) signal frominverter board 204 to power board 200.

Rectifier board 202 is coupled to an extension portion 64 adjacent userinterface board 200. Rectifier board 202 includes a plurality ofmounting holes 210 formed therethrough, including one mounting hole 210in each corner of board 202. A fastener 212 is passed through each hole210 and coupled to endshield 58 to secure board 202 in place. Rectifierboard 202 receives the AC current from user interface board 200, andoutputs a high current DC signal, via any one of a standard connectortype (not shown).

Inverter board 204 is coupled to an extension portion 64 adjacentrectifier board 202. Inverter board 204 includes a plurality of mountingholes 210 formed therethrough, including one mounting hole 210 in eachcorner of board 204. A fastener 212 is passed through each hole 210 andcoupled to endshield 58 to secure board 204 in place. Invertor board 204receives the high current DC signal from rectifier board 202 and theserial communication from user interface board 200, and outputs an ACsignal to stator assembly 30 to drive electrical machine 14 and a lowvoltage DC signal to user interface board 200. The input and outputconnections on invertor board 204 are any one of a standard connectortype (not shown).

In alternative embodiments, if the power requirements for electricalmachine 14 are such that any one board generates excessive heat, themodular configuration of controller assembly 46 enables each of thecircuit boards to be reconfigured to spread the heat generatingcomponents around stator assembly 30. For example, in one suitableembodiment, rectifier board 202 includes a bridge rectifier and a commonmode choke, each of which can generate heat. If the heat generated isdetermined to be excessive, rectifier board 202 can be split into twoseparate boards, such that the bridge rectifier and the common modechoke are placed on respective discrete boards. Each board can then beplaced into a separate extension portion 64 of endshield 58.

As shown in FIG. 2, electrical machine 14 is coupled to fan impeller 12such that electrical machine 14 is positioned entirely outside fanchamber 28, i.e., no portion of electrical machine 14 extends throughrear plate 18 to intrude into chamber 28. Thus, air is able to flowthrough chamber 28 free of disturbances and without being directedaround electrical machine 14, as is the case in at least some known fanassemblies having radial flux motors. Such interference generallyresults in a loss of fan efficiency. Therefore, zero intrusion ofelectrical machine 14 into chamber 28 prevents such a loss in efficiencyand provides for an increase in efficiency of fluid circulating assembly10 as compared to at least some known fluid circulating assemblieshaving radial flux motors that extend a significant distance into thefan chamber.

In the exemplary embodiment, as best shown in FIG. 2, electrical machine14 does not include a shaft or a shaft hub assembly to couple electricalmachine 14 to fan impeller 12. Rather, electrical machine 14 is coupleddirectly to rear plate 18 of fan impeller 12 via drive hub 126 tofacilitate rotation of fan impeller 12 about center axis 24. Morespecifically, drive hub 126 is coupled directly to rotor disk assembly48, and rear plate 18 is coupled directly to drive hub 126 via fasteners164 threaded through corresponding openings (not shown) formed in rearplate 18. Alternatively, rotor disk assembly 48 can be fabricated tocouple directly to rear plate 18, such that drive hub 126 is not needed.In another embodiment, rotor disk assembly 48 is coupled to rear plate18 in any manner that facilitates operation of fluid circulatingassembly 10 as described herein.

FIG. 18 is a cross-sectional view of an alternative fluid circulatingassembly 174. FIG. 19 is a schematic perspective of the alternativefluid circulating assembly shown in FIG. 18, showing a shaft/hubassembly 176 for coupling fan impeller 12 to electrical machine 14. Inthis embodiment, electrical machine 14 includes a shaft 178 coupled toradially inner wall 52 of rotor disk assembly 48. In the exemplaryembodiment, shaft 178 is sized to provide an interference fit with innerwall 52. A keyway 180 is formed in shaft 178 for keying shaft 178 toradially inner wall 52 of rotor disk assembly 48. In alternativeembodiments, shaft 178 is coupled to radially inner wall 52 of rotordisk assembly 48 in any manner that enables fluid circulating assembly174 to function as described herein. In the embodiment shown in FIGS. 18and 19, shaft 178 extends axially away from electrical machine 14 intochamber 28 of fan impeller 12. Shaft/hub assembly 176 includes a hubflange 182 coupled to fan impeller 12 via a plurality of fastener 164.Hub flange 182 includes a generally cylindrical hub portion 184 and anannular flange portion 186 extending radially outward from hub portion184 and located at an end of the hub portion. Hub flange 182 includes ahole (not shown) that is concentric with hub portion 184 and configuredto couple to shaft 178. In this embodiment, shaft 178 is keyed to hubflange 182 and forms an interference fit with the hole (not shown)provided through hub flange 182. Hub flange 182 also includes aplurality of fasteners openings (not shown) configured to receivefasteners 164 for coupling to fan impeller 12. In alternativeembodiments, shaft 178 is coupled to hub flange 182 in any manner thatenables fluid circulating assembly 174 to function as described herein.

In operation, copper windings 44 are coupled to stator core 36 and areenergized in a predetermined sequence by controller assembly 46. Cooperwinding's 44 facilitates generating an axial magnetic field that movesin one of a clockwise and counterclockwise direction around stator core36, depending on the pre-determined sequence in which copper windings 44are energized. The moving magnetic field intersects with a flux fieldgenerated by permanent magnets 54 to generate a torque that causes rotorassembly 32 to rotate about center axis 24 relative to stator assembly30. The generated torques is a direct function of the strength, orintensity, of the magnetic field interactions between cooper windings 44and permanent magnets 54. Because rotor disk assembly 48 is coupleddirectly to rear plate 18 of fan impeller 12, rotation of rotor diskassembly 48 facilitates rotation of fan impeller 12.

The present disclosure provides a fluid circulating assembly withimproved structural designs that improves the air flow entering, passingthrough, and downstream of the assembly. More specifically, a fluidcirculating assembly is disclosed that includes an electrical machinethat is coupled directly to the fan such that the electrical machinedoes not intrude into the inner fan chamber and is positioned entirelyoutside the fan chamber to facilitate preventing interference withairflow within the fan chamber. More specifically, the electricalmachine includes a drive hub that is coupled directly to the rotorassembly of the electrical machine and the rear plate of the fan tofacilitate rotation of the fan. The fluid circulating assembly alsoincludes a substantially planar controller assembly coupled radiallyoutward from the stator assembly. The controller assembly enables a lowprofile housing to cover the electrical machine and the controllerassembly such that the housing extends a minimal distance from the fanrear plate and functions as a large single heat sink for both the statorassembly and the controller assembly. As such, the fluid circulatingassembly takes up less space within a fluid circulating system andprovides for additional space for additional system components.Furthermore, the fluid circulating assembly contains fewer overallcomponents, which provides for a fluid circulating assembly that is lessexpensive and easier to assemble than other known fluid circulatingassemblies.

The apparatus, methods, and systems described herein provide a fluidcirculating assembly having increased efficiency, reduced noise, and animproved airflow distribution through the fan. One advantage to breakingthe controller assembly of the centrifugal fan into modular boardcomponents includes enabling the controller assembly to be favorablyarranged around the outside diameter of stator assembly. Anotheradvantage is that the controller assembly and the stator assembly canshare a common heat sink. Yet another advantage is that the controllerassembly can be arranged such that the modular boards of the controllerassembly can be separated by one or more of a particular board functionand a combination of heat making components. The exemplary embodimentsdescribed herein provide apparatus, systems, and methods particularlywell-suited for HVAC centrifugal blowers.

Further, the embodiments described herein relate to fan assemblies thatinclude a backward curved fan and an axial flux electrical machine thatreduces or prevents airflow interference within the fan and improves theefficiency of the fluid circulating assembly. More particularly, oneembodiment includes a motor coupled to the fan such that the motor doesnot intrude into the fan chamber. The methods and apparatus are notlimited to the specific embodiments described herein, but rather,components of apparatus and/or steps of the methods may be utilizedindependently and separately from other components and/or stepsdescribed herein. For example, the methods may also be used incombination with a forward curved fan or blower assembly, and are notlimited to practice with only the backward curved fan as describedherein. In addition, the embodiment can be implemented and utilized inconnection with many other HVAC applications.

Although specific features of various embodiments of the disclosure maybe shown in some drawings and not in others, this is for convenienceonly. In accordance with the principles of the disclosure, any featureof a drawing may be referenced and/or claimed in combination with anyfeature of any other drawing.

This written description uses examples to disclose the invention,including the best mode, and to enable any person skilled in the art topractice the invention, including making and using any devices orsystems and performing any incorporated methods. The patentable scope ofthe invention is defined by the claims, and may include other examplesthat occur to those skilled in the art. Such other examples are intendedto be within the scope of the claims if they have structural elementsthat do not differ from the literal language of the claims, or if theyinclude equivalent structural elements with insubstantial differencesfrom the literal languages of the claims.

What is claimed is:
 1. A fluid circulating assembly having a rotationaxis, said fluid circulating assembly comprising: a fan impellercomprising an inlet ring and a rear plate that together define a centralfan chamber; an electrical machine comprising a rotor assembly, a statorassembly, and a housing enclosing said rotor and stator assemblies, saidelectrical machine coupled to said rear plate such that said electricalmachine is positioned entirely outside said central fan chamber, saidhousing comprising a plurality of fins on a side of said housingopposite said rear plate, said plurality of fins extending axially awayfrom said stator assembly; and a duct coupled to said housing, said ductcovering a portion of said plurality of fins and extending radiallyoutward from said housing to said rear plate and towards an outer edgeof said rear plate, said duct extends radially beyond a radially outeredge of said rear plate and extends axially a predetermined distancebeyond an axial surface of said rear plate, wherein said duct isconfigured to channel air over said portion of said plurality of fins tofacilitate cooling said electrical machine.
 2. The fluid circulatingassembly in accordance with claim 1, wherein said duct is substantiallyU-shaped in cross-section.
 3. The fluid circulating assembly inaccordance with claim 1, wherein said duct forms a converging taperextending radially from said housing toward said outer edge of said rearplate.
 4. The fluid circulating assembly in accordance with claim 1,wherein said duct further extends axially about said outer edge of saidrear plate, wherein said duct is configured to capture a portion of airejected by said fan impeller and channel the air radially inward oversaid portion of said plurality of fins to facilitate cooling saidelectrical machine.
 5. The fluid circulating assembly in accordance withclaim 1, wherein said housing further comprises an annular centersection, and at least two extension portions extending radially outwardfrom said annular center section.
 6. The fluid circulating assembly inaccordance with claim 5, wherein said fluid circulating assemblycomprises a plurality of ducts, wherein each said extension portioncomprises a second plurality of said plurality of fins, and wherein arespective one of said plurality of ducts is coupled to a respective oneof said at least two extension portions.
 7. The fluid circulatingassembly in accordance with claim 6, wherein each one of said pluralityof ducts extends between said center section and said outer edge of saidrear plate.
 8. A method for assembling a fluid circulating assemblyhaving a rotation axis, said method comprising: providing a fan impellerincluding an inlet ring and a rear plate that together define a centralfan chamber; coupling an electrical machine to the rear plate such thatthe electrical machine is positioned entirely outside the central fanchamber, the electrical machine including a rotor assembly, a statorassembly, and a housing enclosing said rotor and stator assemblies, thehousing including a plurality of fins on a side of the housing oppositethe rear plate, the plurality of fins extending axially away from thestator assembly; and coupling a duct to the housing, the duct covering aportion of the plurality of fins and extending radially outward from thehousing beyond a radially outer edge of the rear plate and extendingaxially a predetermined distance beyond an axial surface the rear plate,wherein the duct is configured to channel air over the portion of theplurality of fins to facilitate cooling the electrical machine.
 9. Themethod in accordance with claim 8, wherein coupling a duct to thehousing comprises coupling the duct to the housing, the duct including asubstantially U-shape cross-section.
 10. The method in accordance withclaim 8, wherein coupling a duct to the housing comprises coupling theduct to the housing, the duct forming a converging taper extendingradially from the housing toward the outer edge of the rear plate. 11.The method in accordance with claim 8, wherein coupling a duct to thehousing comprises coupling the duct to the housing, wherein the ductfurther extends axially about the outer edge of the rear plate, whereinthe duct is configured to capture a portion of air ejected by the fanimpeller and channel the air radially inward over the portion of theplurality of fins to facilitate cooling the electrical machine.
 12. Themethod in accordance with claim 8, wherein coupling an electricalmachine to the rear plate comprises coupling the electrical machine tothe rear plate, the housing further including an annular center section,and at least two extension portions extending radially outward from theannular center section.
 13. The method in accordance with claim 12,wherein coupling a duct to the housing comprises coupling a plurality ofducts to the housing, wherein each extension portion includes a secondplurality of the plurality of fins, and wherein a respective one of theplurality of ducts is coupled to a respective one of the at least twoextension portions.
 14. The method in accordance with claim 13, whereincoupling a plurality of ducts to the housing comprises coupling theplurality of ducts to the housing, wherein each one of the plurality ofducts extends between the center section and the outer edge of the rearplate.
 15. A fluid circulating assembly comprising: an electricalmachine comprising: a rotor assembly; a stator assembly; and a housingcomprising an endshield, said endshield comprising: an annular centersection configured to enclose said stator assembly; a plurality of finsextending axially away from said stator assembly; and a plurality ofaxially extending T-shaped T-slots spaced about a perimeter of saidannular center section of said endshield, wherein said plurality ofaxially extending T-shaped T-slots are integrally formed with saidendshield.
 16. The fluid circulating assembly in accordance with claim15, wherein said endshield further comprises at least two extensionportions extending radially outward from said annular center section.17. The fluid circulating assembly in accordance with claim 16, whereineach one of said plurality of axially extending T-slots is positioned ata respective intersection between said at least two extension portions.18. The fluid circulating assembly in accordance with claim 15, whereineach of said plurality of axially extending T-slots is identical in sizeand shape.
 19. The fluid circulating assembly in accordance with claim15, wherein a narrow opening in each of said plurality of axiallyextending T-slots faces radially outward from said center section. 20.The fluid circulating assembly in accordance with claim 15 furthercomprising: an electrical machine support assembly comprising: aplurality of T-nuts, each one of said plurality of T-nuts engaging withone of said plurality of axially extending T-slots, each of saidplurality of axially extending T-slots having a length; a supportbracket, wherein each one of said plurality of T-nuts is releasablycoupled to said support bracket via at least one mechanical fastener,thereby enabling said electrical machine to be mounted on said supportbracket using said plurality of T-nuts at a plurality of locations alongsaid length of said plurality of axially extending T-slots, saidplurality of T-nuts extending between said support bracket and saidelectrical machine.
 21. A method of assembling a fluid circulatingassembly, said method comprising: providing an electrical machineincluding a housing having a plurality of axially extending T-slotsspaced about a perimeter of the housing, the plurality of axiallyextending T-slots integrally formed with the housing, each of theplurality of axially extending T-slots having a length; slidinglycoupling a T-nut to each one of the plurality of axially extendingT-slots; and releasably coupling each respective T-nut to a supportbracket using at least one fastener, thereby enabling the electricalmachine to be slidingly coupled to the support bracket via the T-nuts ata plurality of locations along the length of the plurality of axiallyextending T-slots.
 22. The method in accordance with claim 21, whereinproviding an electrical machine including a housing comprises providingthe electrical machine including the housing having an endshield, theendshield including an annular center section configured to enclose astator assembly, and a plurality of fins extending axially away from thestator assembly.
 23. The method in accordance with claim 22, whereinproviding the electrical machine including the housing having anendshield comprises providing the electrical machine including thehousing having the endshield, wherein the endshield includes at leasttwo extension portions extending radially outward from the annularcenter section.
 24. The method in accordance with claim 23, whereinproviding the electrical machine including the housing having anendshield comprises providing the electrical machine including thehousing having the endshield, wherein each one of the plurality ofaxially extending T-slots is positioned at a respective intersectionbetween the at least two extension portions.
 25. The method inaccordance with claim 21, wherein providing an electrical machineincluding a housing comprises providing the electrical machine includingthe housing, wherein a narrow opening in each of the plurality ofaxially extending T-slots faces radially outward from the housing.